To compress and decompress using GZip in C# and VB.NET you can use the Following snippet.

Samples

Sample C#

public static byte[] DecompressGZip(byte[] bytesToDecompress)
{
	using (GZipStream stream = new GZipStream(new MemoryStream(bytesToDecompress), CompressionMode.Decompress))
	{
		const int size = 4096;
		byte[] buffer = new byte[size];
		using (MemoryStream memoryStream = new MemoryStream())
		{
			int count;
			do
			{
				count = stream.Read(buffer, 0, size);
				if (count > 0)
				{
					memoryStream.Write(buffer, 0, count);
				}
			} while (count > 0);
			return memoryStream.ToArray();
		}
	}
}

public static byte[] CompressGZip(string input, Encoding encoding = null)
{
	encoding = encoding ?? Encoding.Unicode;
	byte[] bytes = encoding.GetBytes(input);
	using (MemoryStream stream = new MemoryStream())
	{
		using (GZipStream zipStream = new GZipStream(stream, CompressionMode.Compress))
		{
			zipStream.Write(bytes, 0, bytes.Length);
			return stream.ToArray();
		}
	}
}

Sample VB.NET

Public Function DecompressGZip(bytesToDecompress As Byte()) As Byte()
	Using stream As New GZipStream(New MemoryStream(bytesToDecompress), CompressionMode.Decompress)
		Const size As Integer = 4096
		Dim buffer As Byte() = New Byte(size - 1) {}
		Using memoryStream As New MemoryStream()
			Dim count As Integer
			Do
				count = stream.Read(buffer, 0, size)
				If count > 0 Then
					memoryStream.Write(buffer, 0, count)
				End If
			Loop While count > 0
			Return memoryStream.ToArray()
		End Using
	End Using
End Function

Public Function CompressGZip(input As String, Optional encoding As Encoding = Nothing) As Byte()
	encoding = If(encoding, Encoding.Unicode)
	Dim bytes As Byte() = encoding.GetBytes(input)
	Using stream As New MemoryStream()
		Using zipStream As New GZipStream(stream, CompressionMode.Compress)
			zipStream.Write(bytes, 0, bytes.Length)
			Return stream.ToArray()
		End Using
	End Using
End Function

Compatibility: .NET 2.0 .NET 3.0 .NET 3.5 .NET 4.0 .NET 4.5 .NET 4.6

If you have any questions or suggestions feel free to rate this snippet, post a comment or Contact Us via Email.

Related links:

• System.IO.Compression Namespace
• GZipStream Class